HAVANA — A Russian warship was docked in Havana Wednesday, without explanation from Communist Cuba or its state media.

The Viktor Leonov CCB-175 boat, measuring 91.5 meters (300 feet) long and 14.5 meters wide, was docked at the port of Havana’s cruise ship area, near the Russian Orthodox Cathedral.

The Vishnya, or Meridian-class intelligence ship, which has a crew of around 200, went into service in the Black Sea in 1988 before it was transferred seven years later to the northern fleet, Russian media sources said.

The former Soviet Union was Cuba’s sponsor state through three decades of Cold War. After a period of some distancing under former Russian president Boris Yeltsin, the countries renewed their political, economic and military cooperation.

The ship is reportedly armed with 30mm guns and anti-aircraft missiles.

Its visit comes as isolated Havana’s current economic and political patron, Venezuela, is facing unprecedented violent protests against President Nicolas Maduro’s government.

Cuban President Raul Castro’s Communist government is the Americas’ only one-party regime.